Mechanism for folding margins



May 22, 1962 J. J. DECOULOS MECHANISM FOR FOLDING MARGINS Filed May 12, 1960 INVENTOR. JOHN J. DECOULOS MM/ ATTO R N EYS n t-y United States Patent 3,035,288 MECHANISM FOR FOLDING MARGINS John J. Decoulos, Peabody, Mass, assignor to Boston Machine Works Company, Lynn, Mass, a corporation of Massachusetts Filed May 12, 1960, Ser. No. 28,600

3 Claims. (Cl. 12-55) This invention relates to a mechanism for folding a narrow margin of sheet material back on itself to form a smooth rounded edge. In preparing pieces of sheet material such as split leather for assembling to form an article such as a shoe upper, it is often desirable to fold back a narrow marginal portion of the piece so as to avoid the rough appearance of a cut edge. In some cases, backing material may be cemented to a very thin piece of split leather, leaving narrow margins of the leather to be folded over the edges of the backing to form smooth rounded edges for the finished piece. According to the invention, a mechanism is provided for folding margins along the edges of a piece of sheet material the sides of which are straight. The mechanism can be used on such sides even when they meet in such a way as to form a reentrant angle. For a more complete understanding of the invention, reference may be had to the following description thereof and to the drawing, of which:

FIGURE 1 is a perspective view of a machine for folding margins;

FIGURE 2 is an enlarged section on the line 22 of FIGURE 1;

FIGURE 3 is similar to FIGURE 2 but shows the folder in a different stage of operation; and

FIGURE 4 is a perspective view of a work-piece which has been operated on.

For convenience in presenting work-pieces to the folder, a horizontal table is provided, this table having a top of considerable thickness, an edge of which is beveled on its under side, as at 12, to form a moderately sharp lip 14, the bevel 12 forming with the top face of the table an acute angle of about 20 or so.

The active folding member is a cylindrical rod 16 an obtuse sector of which is cut away for its entire length leaving plane faces 18 and 20 which make an angle of about 140 with each other. As indicated in FIGURES 2 and 3, the face 18 is radial with respect to the axis of the rod 16, but the face 20 is offset slightly from the axis to provide clearance as hereinafter explained.

The rod 16 is supported at the edge of the table 10 so i that the sharp lip 14 is at the axis of the rod, the surface 18 of the rod normally being in contact with the bevel face 12 of the table top. To support the rod 16 in such position but to permit it to be rocked about its axis, a thick-walled tubular jacket 22 is fitted coaxially around the rod and is secured by welding or otherwise to a support block 24 removably fastened to the table 10 by screws 26 or the like. The jacket 22 has a longitudinally extending opening or gap 28 in its side, the gap being defined by a face 30 which extends radially from the axis of the tube and a face 32 the direction of the plane of which is not important. The face 30 of the tube bears against the bevel face 12 while the face 32 overhangs a portion of the table near the edge 14. The angle at the axis subtended by the gap is sufficiently larger than 20 to permit easy insertion of a work-piece into the interior of the jacket to be operated on by the rod 16.

To rock the rod 16 about its axis, a series of stems 36 are secured to the rod to project radially therefrom at spaced points along its length. Each of these stems 36 extends through a transverse slot 38 in the wall of the tube 22. Each slot 38 extends circumferentially from the gap 28 part way around the jacket so that the stems 36 can move therein to rock the rod 16. For convenience the stems 36 are all secured to a crosshead 40 which is connected by a link 42 to the end of a rocking lever 44 fulcrurned at 46 on a standard 48. The standard 48 and the table 10 may be supported on a bench or the like (not shown). To provide clearance for the stems 36, the block 24 has transverse slots 50 registering respectively with the slots 38 in the tube 22.

A typical work piece W consists of a piece of thin split leather or equivalent sheet material 60 having one or more straight edges. A backing sheet 62, usually of a different material, is cemented to the back sun-face of the sheet 60, leaving a margin 64 of uniform width approximately equal to the Width of the face 20 of the cut-away sector of the rod 16. When the rod 16 is in the angular position indicated in FIGURE 2, a straight margin 64 of a work-piece is inserted through the gap 23 into the cut-away sector of the rod 16. The lever 44 is then rocked to rotate the rod 16 from the position shown in FIGURE 2 to that shown in FIGURE 3. The margin 64 is engaged by the face 20 and folded about the edge of the backing piece 62 and against the wider side thereof as indicated in FIGURE 3. The offset of the face 20 from the axis of the rod provides just enough clearance between the top face of the table 10 and the surface 20, when these faces are parallel, to prevent crushing the layers of the work-piece pressed between these faces.

The tubular jacket 22 is open at its ends which are preferably flush with the side edges of the table 10. The ends of the rod 16 are flush, or nearly so, with the ends of the jacket 22. Hence the machine can be readily used to fold edges not only along sides of the work piece terminating at outwardly projecting angles but also along sides which meet at reentrant angles such as that indicated at R in FIGURE 4.

The rod 16 operates successfully on margins having a width approximately equal to that of the face 20. If work pieces have margins of other widths, the assembly consisting of the block 24, the tube 22, the rod 16, the stems 36 and the cross-head 40, can readily be replaced by another assembly having a rod of different size.

I claim:

1. Apparatus for folding margins of sheet material, comprising a table having a straight side edge, said table being beveled on its under side along said edge forming an acute angled lip at said edge, a cylindrical rod extending along said edge, said rod having an obtuse sector thereof cut away leaving a sector with two plane faces, supporting means for said rod consisting of a tube in which said rod is rotatably fitted, said tube having a portion thereof cut away forming a longitudinal gap in the wall thereof, means supporting said tube along said edge of the table with the tube wall at one side of said gap engaging the underside of said lip and the tube wall at the other side of said gap spaced above the top face of the table, and means operable to rock said rod about its axis from a position of interfacial contact between one plane face of said rod and the under face of said lip and a position in which the other plane face of the rod is parallel to said table.

2. Apparatus as described in claim 1, said rod-operating means comprising stems extending radially from said rod, said tube having slots through which said stems extend respectively and in which they are free to move when the rod is rocked, and means attached to all of said stems and movable to rock said rod about its axis.

3. Apparatus for folding margins of sheet material comprising a horizontal table of substantial thickness having a straight side edge beveled underneath to an angle of about 20, a rod having a cutaway sector of about rockably supported along said edge with its axis substantially at said edge and one side of the cutaway sector normally bearing against the bevel surface on the under side of the table, a thick-walled tube in which said rod is rockably fitted, said tube having a gap in its wall extending the entire length thereof and a series of spaced slots extending circumferentially from one side of said gap part-way around toward the other side, means supporting said tube along said edge of the table with one side of the gap against said bevel surface and the other side of the gap spaced above the top face of the table, and means for rocking said rod about its axis, said means comprising References Cited in the file of this patent UNITED STATES PATENTS 1,210,761 Chatfield Jan. 2, 191,7 

